According to statistic, among couples of child-bearing age all over the world, the rate of sterility is about 15%, and about 40% of the factors causing the sterility are attributed to the husband's side. Since the 20th century, the fertility of male obviously tends to decrease all over the world due to environmental pollution, spreading of social disease and AIDS, excessive smoking and drug addiction, abuse of hormones medicament, and etc.
On the one side, the study in epidemiology demonstrates that, among men of above 20 ages in USA, the incidence rate of erectile dysfunction is 18.4%. If calculated according to the statistic of census made in 2000, the number of men who suffer from this disease in USA shall be in the order of 18 millions. The incidence rate of this disease is closely relevant to age, varying from 5.1% (men aged 20-39) to 70.2% (men aged above 70). As a whole, 65.0% of men can always have normal erection and fulfill coitus; 16.5% of men can have normal erection in general cases; 12.3% of men occasionally can have erection and fulfill coitus; and 6.2% of men never have normal erection. As a PDE5 inhibitor for oral administration, Sildenafil relieves the pain of up to millions of patients suffering from sexual dysfunction, but some side effects as subsequently resulted therefrom are also very serious.
On the other side, as reported, since 1940 to 1990, the number of sperms contained in per ml of semen of adults decreases from 1.13×108 to 6.6×107, and the amount of semen decreases from 3.40 ml to 2.75 ml. As compared with the situation in 1940, the sperm density of men all over the world decreases by 50%, i.e., decreases by 1% per annual in average. In addition to the decrease in number of sperms, the ratio of active sperms and the ratio of sperms in normal shape also decrease year after year (which decrease by 0.6% and 0.5% per annual, respectively). The continuous decrease in quality of semen directly leads to reduced fertility and reproductive function, which has gradually become an obvious social problem. One of crucial factors causing male sterility is the decrease in quality of sperms (number and motility of sperms), so it is very important to search for a medicament that can improve the quality of sperms. However, until now, there is still no medicament all over the world that has an exact therapeutic effect, and can increase the number of sperms and improve the activity of sperms.
Therefore, in reproductive medicine field, it has long been a difficult problem yet to be solved to develop a medicament capable of improving sexual function of male mammals, in particular men, increasing number of sperms, and improving quality of sperms.
In order to solve the above problem, the present inventors discovered upon a lot of researches that plant-derived ginsenoside Rg1, in particular its metabolites ginsenoside Rh1 and/or Ppt, can effectively improve sexual function of men, promote spermatogenesis, increase number of sperms, and improve quality of sperms.